Japanese Patent Application Publication No. 2008-238792 discloses a liquid-ejection device including a main body and a cartridge. The main body includes a liquid-ejection head and a sub-tank. The cartridge has a liquid storage chamber and is detachably attachable to the main body.
Ink in the liquid storage chamber flows into the sub-tank in accordance with outflow of the ink from the sub-tank to the liquid-ejection head. Both of the sub-tank and the liquid storage chamber are in communication with an atmosphere. Therefore, a liquid level of ink in the sub-tank eventually becomes equal to a liquid level of ink in the liquid storage chamber.